KOLKATA: Economic growth is reducing faecal pollution in groundwater in North India, which is a key factor causing water-borne diseases in the densely populated Indo-Ganges-Brahmaputra river basin, a study by researchers at IIT Kharagpur has found.
About 100,000 children in India die every year from waterborne enteric diseases like diarrhoea, researchers said. The study, published in the International Journal of Information Management, made first-time observations on a significant reduction of faecal coliform pathogen concentration in the spatially variable groundwater from 2002 to 2017.
"Looking beyond the country globally, more than two billion people, mostly living in economically stressed areas of Africa and South Asia still do not have access to basic sanitation, and more than one billion still opt for open defecation," said Professor Abhijit Mukherjee, from the Department of Geology and Geophysics at IIT Kharagpur in West Bengal.
"The resulting unsafe disposal of faecal waste to nearby drinking water sources poses an extremely serious environmental crisis and public health concern," said Mukherjee, who led the research project.
The researchers studied data for the densely populated Indo-Ganges-Brahmaputra river basin, across 234 districts in Rajasthan, Haryana, Uttar Pradesh, Bihar, Jharkhand, Chhattisgarh, West Bengal, Assam and also Delhi and NCR.
The data was collected from National Rural Drinking Water Programme, Ministry of Drinking Water and Sanitation, and covered almost last three decades to delineate the long-term improvement trends of groundwater quality across India, as consequence of development.
The study determined the economic development trends and correlations using nigh-time light data instead of gross domestic product (GDP) or other economic growth data.
"Night-time light is regarded as a secular proxy for economic growth and in recent times are regularly used as a modern technique for characterising micro-GDP -- GDP for a small area," Mukherjee said.
"We have used satellite-based night-time light information based on Defence Meteorological Satellite Program of the US Air Force, archived by NOAA/NASA for the period 1992-2013," said Srimanti Duttagupta, PhD scholar at IIT Kharagpur.
"In most areas economic development, suggested by increasing satellite-based nightlight correlated to the reduction in faecal coliform concentration and alleviation of water quality," said Duttagupta, first author of the research paper based on the study.
The other dataset used was high-resolution geographically spatial information of water-borne faecal pathogen concentration in groundwater from the period 2002-2017.
Numerical and statistical analyses were performed on datasets to understand the efficiency of development in alleviating the water quality and public health, and relationship with economic development.
The study showed that the spatially variable groundwater faecal pathogen concentration from 2002-2017 has significantly decreased across the basin.
From 2002-2013, night-time light on the surface area as seen from satellites increased by 3.05 per cent per year and faecal coliform pollution decreased 1.39 per cent per year.
The research group observed significant decrease of groundwater faecal coliform concentration after 2014, in the acquired data.
"Nevertheless, in areas with inferior water quality, improper human practices outweigh economic development in affecting human health," he added.
It was observed that areas with lower literacy rate and very high population density suffer from poor groundwater quality because of faecal coliform pollution, irrespective of economic development.
The issue of overpopulation and slums is an intricate problem which is reflected on all life aspects in countries like India, researchers said.
The study reflects through results that higher faecal coliform concentration in urban and peri-urban areas, suggesting economic progress may not be the only influencing factor on water quality alleviation, they said.
The researchers noted that social behaviour and practices, use and disuse and beliefs are mostly related to lower literacy rate.
In turn, this result in lack of awareness and encourage malpractice on sanitation, eventually leading to increased faecal waste into drinking water sourced to groundwater, according to the study.